Traditionally, most airline carriers manually assign routes to aircraft. This usually involves having experts allocate all candidate flight segments to specific aircraft tail numbers (unique sequence of alphanumeric characteristics used to identify a specific aircraft) within a given sub-fleet of the airline. In addition to any requirements of the flight segments, the experts must ensure the allocations meet the operational and maintenance requirements of the aircraft. Considering that some carriers may have hundreds of aircraft and thousands of flights scheduled over a given time period (e.g., a month), this can be a complex and cumbersome process. This problem is not necessarily unique to the airline industry, it applies to carriers of other modes of transportation.
Further, during the normal operations of a carrier, situations may often develop wherein modifications have to be made to the existing schedule plan. For example, an aircraft may unexpectedly be grounded, thus leaving all flights that were assigned to the aircraft's route without an aircraft. Since most carriers would not willingly give up the revenues generated by the flights, experts must re-allocate and shift resources in order to accommodate the orphaned flights. If this happens only on rare occasions, then the traditional manual approach might be acceptable.
In other instances, however, airlines may find it necessary to adjust their flight schedules on a regular basis. For example, passenger demand may require daily adjustments to flight schedules because the demand inherently varies over the course of the week. Manually re-planning the assignments of the aircraft and flights to accommodate these adjustments may be inefficient. Further, given the necessity to produce a plan within short time constraints, a generated plan may not be fully calculated to maximize revenues for the airline.
Therefore, it would be beneficial to develop efficient solution procedures that can determine feasible aircraft routings over a given time period while considering all operational and maintenance constraints. These procedures could be used to make the initial aircraft routing and/or update the routing as necessary.